Romney, the GOP nominee in 2012, suggested that a "bombshell" was
hidden somewhere in Trump's tax documents:

Well, I think there's something there. Either he's not anywhere
near as wealthy as he says he is, or he hasn't been paying the
kind of taxes we would expect him to pay. Or perhaps he hasn't
been giving money to the vets or the disabled, like he's been
telling us he's been doing.

Romney was dogged by questions over his own tax returns in the
2012 race. Trump, a billionaire real-estate developer, has
insisted that his tax filing is simply too complicated to release
quickly.

Trump
responded to Romney's interview by calling him a "fool" and
"goofy" on Twitter. On Wednesday night, he also retweeted a small
flurry of supporters using insults like "pathetic" and "jealous"
to describe Romney: